Costa Rica's environment ministry, Setena, had warned of the negative environmental impact caused by construction of the San José-Caldera highway a year before it was opened, according to Danilo Vindas Chaves of the ministry's audit department.

Setena began an inspection based on a complaint brought to the ministry by the national conservation system Sinac, Vindas told a congressional committee analyzing concessions.

The audit department had reported flaws in construction, including problems with the stability of retaining walls, the congressional website reported. The report also indicated that construction had impacted the Barva aquifer, harmed plant life, and affected biological systems and archeological sites.

"We concluded that the environmental impact studies and environmental management plans were not carried out in the best way, causing a severe negative environmental impact," Vindas said.

The 77km highway opened in January 2010. In June of the same year, landslides prompted the public works ministry (MOPT) to close an 11km stretch for several weeks.